# Classic Category Line Renderer Odd Behavior on None Values

**URL:** <https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647>\
**Category:** Ignition\
**Created:** [February 6, 2017, 6:02pm UTC](https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647 "2017-02-06T18:02:02Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![bfearnow](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/bfearnow/32/3337_2.png) [@bfearnow](https://forum.inductiveautomation.com/u/bfearnow)\
**Post date:** [February 6, 2017, 6:02pm UTC](https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647/1 "2017-02-06T18:02:02Z")

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Hello. I built kind a funky “waterfall” chart in Ignition for downtime percentages. I am using a rolling subtraction for the bars in white and stacking the percentage of actual downtime on top for the effect. I also have a line chart in front that shows the downtime occurrences by category.

[attachment=1]Chart SS.png[/attachment]

The capacity, unaccounted, and tmax marker will always be @ 0 for the line graph so I tried passing “None” in. This works, but when you hover over the bars it gives me a [] where there should be a number, even on datapoints that do not have the “None” value. Any suggestions?

[attachment=0]Chart SS With None Values.png[/attachment]

Thanks!

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [February 6, 2017, 9:13pm UTC](https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647/2 "2017-02-06T21:13:30Z")

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Add either of the following to the configureChart scripting extension to hide the tooltips:

`	renderer = chart.getPlot().getRenderer()
	renderer.setBaseToolTipGenerator(None)`

`	from org.jfree.chart.labels import CategoryToolTipGenerator
	class CustomToolTipGenerator(CategoryToolTipGenerator):
		def generateToolTip(self, dataset, row, column):
			return None
	renderer = chart.getPlot().getRenderer()
	renderer.setToolTipGenerator(CustomToolTipGenerator())`

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**Author:** ![bfearnow](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/bfearnow/32/3337_2.png) [@bfearnow](https://forum.inductiveautomation.com/u/bfearnow)\
**Post date:** [February 8, 2017, 2:15pm UTC](https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647/3 "2017-02-08T14:15:10Z")

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I am doing a poor job explaining the issue, but I actually want the tooltips. I also want None values in the dataset so that certain points and lines don’t show up. For some reason though, when there are none values in the chart dataset, it ruins all of the tooltips (even where there is good numbers). It shows up with a [].

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**Author:** ![robert.crawford](https://avatars.discourse-cdn.com/v4/letter/r/5e9695/32.png) [@robert.crawford](https://forum.inductiveautomation.com/u/robert.crawford)\
**Post date:** [October 5, 2021, 8:17pm UTC](https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647/4 "2021-10-05T20:17:40Z")

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I am looking to have a waterfall representation of downtime. Cna you share how you did this?

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**Author:** ![bfearnow](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/bfearnow/32/3337_2.png) [@bfearnow](https://forum.inductiveautomation.com/u/bfearnow)\
**Post date:** [October 18, 2022, 8:11pm UTC](https://forum.inductiveautomation.com/t/classic-category-line-renderer-odd-behavior-on-none-values/12647/5 "2022-10-18T20:11:41Z")

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I am sorry Robert, but that was 5 years and a career change ago. I don't have access or recall exactly how it went.